The Argentinean, who won the 14th ATP title of his career in Rotterdam recently, came close to losing the contest at 4-5 in the deciding set but battled back to take it on a tiebreak.

He's a great player," del Potro told the ATP Tour's official website. "He fights like me every point, and we had fantastic rallies. I'm so glad to beat him tonight in Dubai.

"I played fantastic forehands to keep playing this match. Then in the end, of course, you need a little bit of luck to win these kinds of matches, and I think I played solid on important points in the third."

Tomas Berdych, the No. 3 seed, had no such problems as he accounted for American wild card Rajeev Ram 6-1 6-3 in less than an hour.

The 27-year-old was runner up to Jo-Wilfried Tsonga at last week's Marseille Open, despite having a match point. He made the Dubai semis in 2011, losing to Djokovic.

Nikolay Davydenko edged past the No. 6 seed, Janko Tipsarevic of Serbia. The Russian, who is retiring at the end of this year, triumphed 6-0 7-5.

There were also victories on Thursday for Marcel Granollers, of Spain, Romania's Victor Hanescu, Tobias Kamke, from Germany and Russia's Dmitry Tursunov.